There are currently three licenced cannabinoid medicines each of which contains a compound that can activate CB1 and CB2 receptors [21]. Two of these medicines were developed to suppress nausea and vomiting produced by chemotherapy. These are nabilone (Cesamet®), a synthetic CB1/CB2 receptor agonist, and synthetic Δ9-tetrahydrocannabinol (Marinol®; dronabinol), which can also be used as an appetite stimulant. The third medicine, Sativex®, contains mainly Δ9-tetrahydrocannabinol and cannabidiol, both extracted from cannabis, and is used to treat multiple sclerosis and cancer pain.

Comments

Both CB1 and CB2 receptors may be labelled with [3H]CP55940 (0.5 nM; [33]) and [3H]WIN55212-2 (2–2.4 nM; [35-36]). Anandamide is also an agonist at vanilloid receptors (TRPV1) and PPARs [19,39]. There is evidence for an allosteric site on the CB1 receptor [24]. All of the compounds listed as antagonists behave as inverse agonists in some bioassay systems [22]. For some cannabinoid receptor ligands, additional pharmacological targets that include GPR55 and GPR119 have been identified [22]. Moreover, GPR18, GPR55 and GPR119, although showing little structural similarity to CB1 and CB2 receptors, respond to endogenous agents that are structurally similar to the endogenous cannabinoid ligands [22].